The aim of this project is to uncover, assess and contrast mechanisms that are responsible for impairments in cognitive functioning in different forms of neuropsychiatric disorders, emphasizing syndromes that are associated with alcohol abuse. A cognitive neuroscience prospective along with brain imaging and neuropharmacological methods are used to consider how disordered cognitive functioning in alcoholics is involved in the development and maintenance of alcohol addiction and abuse. Research studies have been designed to test a set of hypotheses that suggest there are selective impairments in strategic use of cognitive planning and evaluative functions (as expressed in the ability to appropriately inhibit behaviors, use conceptually-driven plans, in contrast to data or stimulus-driven cognitive operations, use of meta cognitive processes, such as monitoring the source of what is remembered). Research findings demonstrate that many detoxified alcoholics exhibit: cognitive impairments such as an inability to learn from experience in both explicit and implicit remembering; a failure to inhibit errors in learning and remembering; an inability to track the source of remembered knowledge (an effect associated with decreased glucose utilization in left anterior temporal lobe and prefrontal brain regions); a slowing in reaction time in carrying out simple cognitive tasks (such as in attention). They also have difficulties in allocating cognitive resources in a strategic fashion. Likewise, in an attention task that is specifically designed to examine the role of inhibitory functions (under a variety of conditions) we have found that detoxified alcoholics have difficulties in ignoring irrelevant information in attention, and this effect mirrors their inability to strategically and effectively process information in learning and remembering. Like some amnestic patients, they are also unable to use implicit (subjective) knowledge in the service of cognitive decisions, yet, at the same time they are less sensitive to having multiple opportunities to rehearse and encode information in learning and remembering. There are qualitative differences in the cognitive style of alcoholics that differentiate them from normal volunteers. We have found that the cognitive responsivity ('style') of alcoholics, as well as polydrug abusers, are more likely to be defined by external stimuli rather than conceptually (internally) driven goal-directed cognitive processing that characterizes the information processing style of normal volunteers. The pattern of impairments observed in alcoholics is unlike the kinds of cognitive changes apparent in other neuropsychiatric disorders (e.g., depression) and also differs from the pattern of cognitive changes associated with normal and pathological aging. The cognitive changes associated with normal aging are apparent across a wide array of functions. In examining cognitive aging effects we have uncovered some of the ways in which explicit remembering plays a role in implicit perceptual and conceptual learning.